Scientists have figured out how rorqual whales can stretch their mouths to double the size while feeding. These massive whales have a bungee cord-like nerve structure in their mouths and tongue that allow expansion without damaging the nerves, according to researchers at the University of British Columbia.

 To eat, rorqual whales open their mouths and lunge while their tongues invert and their mouths fill like giant water balloons full of floating prey. The whales' nerves are stretchy so they can withstand the tissue deformation. Credit: Vogl et al./Current Biology 2015 via Phys.org. Image 1. To eat, rorqual whales open their mouths and lunge while their tongues invert and their mouths fill like giant water balloons full of floating prey. The whales' nerves are stretchy so they can withstand the tissue deformation. Credit: Vogl et al./Current Biology 2015 via Phys.org

In humans, stretching of the nerve usually damages it. But in whales, the nerve is coiled inside of a central core which allows it to expand without actually stretching.

 A segment of a tongue nerve at its initial length prior to being stretched. The nerve has been manually stretched to more than twice its initial length until it abruptly resists further extension. Credit: University of British Columbia via Phys.org. Image 2. A segment of a tongue nerve at its initial length prior to being stretched. The nerve has been manually stretched to more than twice its initial length until it abruptly resists further extension. Credit: University of British Columbia via Phys.org

"This discovery underscores how little we know about even the basic anatomy of the largest animals alive in the oceans today," says Nick Pyenson of the Smithsonian’s National Museum of Natural History.